They sure are! And they're even more: IMVironments can be used to convey a feeling or emotion (falling snowflakes?); play interactive games (doodle together?); or share exclusive photos, music, and other forms of media.
Just click the IMVironment button at the top of the conversation window to see what your options are.
There may also be one or two graphical buttons at the top of the window that provide quick access to the newest IMVironments. Click them once to load the IMVironment; click again to unload your selection.